https://www.youtube.com/watch?v=dD4kbSBaN7o Seen in: The Springfield Files (Season 8, Episode 10) It is hugely difficult to pick the single best TV parody ever on The Simpsons but you could do far worse than choosing this terrific comedy crossover between two shows you never thought would meet - The Simpsons and The X-Files. Gillian Anderson and David Duchovny brilliantly send up their own characters; particularly Duchovny, who gets to make fun of Mulder's long-winded speeches about extra-terrestrials and the character's cockiness (look out for his FBI ID photo). There are also some easter eggs for X-Files fans to spot, including the mysterious Smoking Man lurking in the background of one scene. The episode is a spot-on parody of The X-Files' stand-alone episodes, which often involve Mulder and Scully investigating alien sightings in the heartland of America. It also squeezes in references to many other sci-fi films and TV for good measure, everything from Star Wars to Alf. Plus, the whole thing is held together by Leonard Nimoy's hilarious narration. Now that The X-Files has returned to our screens, it is a good time to revisit The Simpsons' take on it. The laughs are out there... What's your favourite TV parody in The Simpsons? Let us know in the comments!